Cuesta College, San Luis Obispo, CA
An LP record[*] has a rotational inertia of 1.46×10–3 kg·m2, and rotates at a rate of 3.5 rad/s. The record can be considered a solid disk (Idisk = (1/2)·M·R2). If the LP record then rotates at a slower rate, it would have __________ rotational inertia.
(B) the same.
(D) (Not enough information is given.)
[*] Peter Atkins, Julio de Paula, Physical Chemistry (9th ed.), W.H. Freeman and Co. (2009), p. 318.
Correct answer (highlight to unhide): (B)
Since rotational inertia of the LP record depends on its mass M and radius R, which do not physically change whether rotating at a faster or slower rate, then the rotational inertia remains constant.
Sections 70854, 70855, 73320
Exam code: quiz05bL8D
(A) : 24 students
(B) : 32 students
(C) : 9 students
(D) : 0 students
Success level: 48%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.74